Gas turbine control



Dec. 28, 1948. A. w. ORR, JR

GAS TURBINE CONTROL 6 Sheets-Sheet 1 Filed July 22, 1946 a r w W H INVENTOR.

vqTTOR/VEY Dec. 28, 1948. A. w. ORR, JR

GAS TURBINE CONTROL 6 Sheets-Sheet 2 Filed July 22, 1946 A W 0212" c713 INVENTOR.

Dec. 28, 1948. A. w. ORR, JR

GAS TURBINE CONTROL 6 Sheets-Sheet 5 Filed July 22, 1946 Ala/201a INVENTOR.

HTTOP/YE Y Dec. 28, 1948. A. w. ORR, JR

GAS TURBINE CONTROL 6 Sheets-Sheet 4 Filed July 22, 1946 INVENTOR.

Orr

Dec. 28, 1948. A. w. ORR, JR

GAS TURBINE CONTROL 6 Sheets-Sheet 5 Filed July 22, 1946 Hl I/I 012mb:

INVENTOR.

IqTTO/P/VEV Dec. 28, 1948. A. w. ORR, JR 2,457,595

GAS TURBINE CONTROL Filed July 22, 1946 6 Sheets-Sheet 6 HW Orr Q12:

1 N VEN TOR.

Patented Dec. 28, 1948 GAS TURBINE CONTROL Andrew William Orr, In, Detroit, Mich., assignor to George M. Holley and Earl Holley Application July 22, 1946, Serial No. 685,520

18 Claims. 1

airplane in which the motive power is a gas turbine. It can also be applied to the control of a stationary gas turbine.

The specific object of this invention is to maintain a fixed final temperature in the turbine entrance, the value of which can be selected manually. The theory of the invention is that the maximum turbine entrance temperature is equal to the temperature of the air entering the combustion chamber plus the rise in temperature in the combustion chamber. The latter depends on the fuel/air ratio. By measuring temperature indirectly the difiiculties inherent in the direct measurement of high temperatures are avoided.

The control of the output of the gas turbine may be obtained by four alternative methods.

(a) By moving the conical element in and out. This varies the effect of jet propulsion. The temperature is controlled by holding the tail position so as to adjust the load and hence to adjust the output of the turbine. As the air flow increases the fuel/air ratio decreases and the temperature falls. As the air fiow decreases the temperature rises. It is desirable from a thermodynamic point of view to maintain the temperature at the highest possible safe value. If the temperature control moves the tail control in, which means to a high load position, a higher temperature may result than may be desirable. The turbine speed may also tend to rise so that a centrifugal governor is provided which tends to supply less fuel so as to maintain the desired speed. The temperature and turbine speed are thus both maintained at the desired selected values.

(b) By varying the propeller pitch on a turbine driven propeller so that the temperature control regulates the pitch to maintain the selected inlet turbine temperature. This control of load operates in conjunction with the fuel flow which is controlled by a speed governor to maintain the desired speed. With this alternative construction instead of moving the tail element the propeller pitch is varied. I

By varying the propeller pitch with a conventional means. Specifically by manually controlling the speed of the governor which controls the propeller pitch. In this case there will be no governor controlling the fuel and there will instead be a manual selection of the desired turbine inlet temperature. The fuel will be controlled automatically to give this maximum combustion chamber temperature by regulating the fuel flow.

(d) Where there is no propeller a speed governor, responsive to the turbine speed, controls the position of the cone in the tail of the jet propulsion. This cone is moved in and out to control the speed of the turbine. As before, there is a manual control for the selected turbine inlet temperature and this device controls the fuel flow to give the selected temperature.

Fig. 1 shows diagrammatically the control which is the subject of this invention.

Fig. 2 shows the general arrangement of the control device applied to an ariplane driven by gas turbine and jet propulsion.

Fig. 3 shows the general arrangement of the control device applied to a propeller driven airplane with auxiliary jet propulsion.

Fig. 4 shows a similar construction to Fig. 3 with an alternative application of the control mechanism shown in Fig. 1.

Fig. 5 shows a general arrangement of the control device applied to an airplane driven by a gas turbine and by jet propulsion. This is an alternative application of the control mechanism shown in Fig. 1.

Fig. 6 is a diagrammatic illustration of the device responsive to fuel/ air ratio.

Fig. 7 is a diagrammatic drawing of the means that indicate turbine inlet temperature.

Referring to Figs. 1 and 2, I0 is the compressor outlet. As the temperature in the compressor outlet rises the element I2 becomes heated and causes the element M to move to the right. The tubular element l5 connected thereto is provided with a port 5 which regulates the pressure acting on the diaphragm I8. By this means the differential pressure acting on the diaphragm I8 is regulated by the temperature in the outlet 10 from the compressor 68. Meanwhile the turbine driven oil pump 20 is imposing a 20 pound per square inch pressure on the port 5 and this 20 pound per square inch is regulated by the load on the relief valve 22 which is spring loaded. There is a restriction 24 above the chamber 26 and to the right of the diaphragm l8. The restriction 24 is in series with the port I6. The downstream pressure on the restriction 24 is the pressure in the chamber 28 which is the inlet pressure leading to the oil pump 20. A pipe 30 connects the outlet from the restriction 24 with sure to the the chamber as. The chamber :2, to the left or the diaphragm. I8, is in free communication through the pipe 34 with the pressure side of the oil pump 28.

The diaphragm 36 is subjected to a corresponding pressure differential derived from perature rise in the burner chamber. The sum of these two temperatures, that is the burner chamber temperature rise and the compressor outlet temperature, is equal to the total temperature entering the turbine and this temperature the output and life at any given speed. In order to select a desired turbine inlet temperature a temperature selector lever 38 is manually operated. Thecam 48, operated by the lever 38, engages with the spring 4I which in its turn engages with the servomotor valve 42. This servomotor valve 42 en ages with the diaphragms I8 and 36. When an increase in temperature is desired the servomotor valve 42 is moved to the left by the clockwise rotation of the cam 48. This causes the element 44 to move to the right which causes the electrical circuit to move the tail element 48 in Fig. 2 to such a' position that the temperature rises so as to bring the servomotor valve 42 back to its position of equilibrium in which it is shown. When the element 48 moves the temat the turbine entrance is critical and determines a the chamber 28. The pressure in the chamber 68, to the left of, the diaphragm 36, is equal to the pressure in the chamber 32 to the left of the diaphragm I8. That'is to say, it is equal to 20 pounds Per square inch. Hence, it is necessary to make the V shaped port 68 move in response to changes in fuel/air ratio which is a measure of the rise in temperature in the combustion chamber. The amount of air that is flowing is determined by the Pitot tubes 58 and 68 in Fig. 2. A needle valve 62 controls the flow from the pipe 58 to the pipe 60 through the restriction 64. The needle valve 62 is connected to the thermom- 7 eter bulb 66 located in the entrance to the compressor 68. Pipe 18 is connected to the bellows I2 which moves the needle 62. The chamber I4 surrounds the bellows I2 and is connected to the pipe 68. The pipe 16 is connected to the pipe 88 past the needle valve 62. By this means, referring to Fig. i, the pressure on the diaphragm 88. which is in ,an upward direction, depends on the volume and temperature of air entering the compressor 68. 'The pressure difference derived from the Pitot tube 58-68 is thus imposed on the diaphragm 88 with a suitable correction for temperature. The servomotor valve 82 controls the position of the loaded piston 84 so that as the air flow falls the servomotor valve 82 descends and the piston 84 moves to the left because the pressure from the oil pump 28 is then transmitted,through the pipe I26 past the servomotor valve 82 to the pipe I21 which transmits oil presright hand side of the. piston 84. Meanwhile oil escapes from the left hand side of piston 84 through the pipe I28 to the return pipe I24. Fuel/air ratio depends on the rela--- tive air flow and fuel flow. Fuel flow originates in the passage 86 and a small portion of it new into the chamber 88, above the fuel diaphragm 88. through the fuel restriction 82, through the pipe 84, past the valve 86, to the gas turbine through the pipe I88. In the position shown the port 88 is almost fully open and through it flows the major portion of the fuel. The main flow of fuel is from the pipe 86 through the port 88 to the pipe I88; The Pitot tube measures the air flow. and the pressure drop at the restriction 82 measures the fuel flow when the valve 86 is wide open. If the air flow is relatively less than the fuel flow the servomotor valve 82 moves down and the piston 84 moves to the left and the valve .86 moves to the left to restore the balance by decreasing the fuel flow through the bypass 84. In order to correct for the fact that air is a fluid which expands, whereas the expansion of kerosene is negligible, a barometric element I82 is added. The outer chamber surrounding the element I82 is I84 and is connected through-the passage I86 with the suction side I6 of the Pitot tube. A small restriction II8, connected'to the atmosphere, insures that there is a deflnite circulation of air in the chamber I84 surroundmg I 82.

The main volume of the fuel flows in at 86. through the port 88 to'the outlet I88 leading to the combustion chamber. The drop across the metering fuel port 88 is the measure of the flow through the port 88. Hence the drop through the restriction 82, when the valve 86 is wide open,

is a measure of the flow through the port. This is the leanest fuel/air ratio that will burn. If the valve 86 moves to the left the drop across 82 no longer reflects the flow through the port 88 but only a fraction of that drop. Hence the position of the valve 86 and therefore the position of the 'port 68 reflects the fuel/air ratio. Hence the cam 48 selects the maximum temperature by means of the servomotor valve ,42 and the electrical connection. By this means the diaphragm 88 is balanced against the diaphragm 88. It follows, that the position of the valve 86 indicates the value of fuel/air ratio (see Fig. 2). It follows from this that any one position of the V shaped orifice 68 determines that there is a corresponding position for the valve 86. 68 is in series with the Jet II6 so that 68 and H6 being in the 011 system, the diflerence in pressure in the two sides of the diaphragm 38, that is to say in the chamber 64 to the right of the diaphragm 36 and chamber 66 to the left of diaphragm 36, :eflects the rise in temperature due to combusion.

The fuel tank II 8 is connected so that it imposes a low pressure on the diaphragm I28 and it also delivers a corresponding pressure on the diaphragm I 22. out. One end of the valve 86 engages with the diaphragm I22. The left hand side of the diaphragm I22 is connected with the return oil pipe I24.- The right hand side of the diaphragm I28 is connected with the return oil pipe I24.

The lower side of the diaphragm I28 and the up- These two pressures cancel r the low pressure side of the diaphragm 88 downstream of the restriction 92.

In Fig. 2 H8 is the fuel tank, I88 is the outlet,

I38 is the screen at the entrance to I88, I40 is I80. The governor is driven by the bevel gear I94. By means of a speed selector lever I80 the turbine speed is controlled. The governor acts by returning a portion of the fuel through the bypass I52 to the inlet side of the pressure pump I44. The compressor 88 drives a pair of bevel gears I54 and the motion is transmitted to another pair of bevel gears I88. Shaft I88 is thus driven at less than the speed of the gas turbine. A pair of bevel gears I80 drives the boost pump I40 and the high pressure pump I44 by means of the shafts I42 and I58. The shaft I58 also drives the centrifugal device within the governor casing I48 by means of the bevel gear I94. The return valve 202, controlled by the governor insidethe casing I48, controls the return of fuel through passage I52. The manual control'lever I80 selects the desired turbine speed. The shaft I88, through a pair of bevel gears I84 and a shaft I88 drives an oil pump 20.

When the hydraulically operated servomotor 44 moves in either direction it energizes one of two electric motors I 88-I10. The electricity is provided from a storage battery I12 and a conductor I14 which delivers electricity to the two motors I68-I10. The servomotor valve 42 determines which of the two conductors I18'I18 will be grounded. The two electric motors I88- I10 drive a shaft which carries a worm I82. One motor turns it clockwise and the other motor turns it anti-clockwise. The worm I82 is thus rotated and the arm I18 thus moves the cone 48 which regulates the flow of 'air through the compressor 68 and the turbine I11 and thus determines the temperature of the inlet to the gas turbine.

The fuel delivered by the governor mechanism I46 descends through the passage 88 and is discharged through the outlet IM to the fuel nozzles I III-I I 4 which delivers fuel past the ignition device I08.

The turbine inlet temperature selector lever 38 is shown on the outside of the casing containing the mechanism shown in Fig. 1.

Fig. 3 corresponds to Fig. 2 with this exception that the turbine I11 drives the propeller I80 by means of spur gears |82l84. The pitch of this propeller is varied by a mechanism contained in the box I81; This mechanism is controlled by the electric conductors I18I18 which are controlled by the movable element 44 (see Fig. 1). Two small electric motors I88I88 are controlled alternately by the electric conductors I18I 18 so that as the temperature responsive element 44 moves to the left and right the two small electric motors I88I 88 make a corresponding adjustment to the propeller I80. The pitch of the propeller is controlled by. a well known hydraulic mechanism controlled by the motors I88-I88. As in Fig. 2 a shaft I88 rotated by the turbine I11 operates the governor by bevel gears I94 which operates the fuel governor-inside the casing I48. This governor mechanism I48 returns excess fuel past the valve 202 through the pipe I52 to the entrance of the high pressure 6 pump I44. The governor mechanism I48 discharges fuel through the passage 88 and this fuel is in its turn discharged through the outlet I00 to the Jets I I4I I0 in the combustion chamber and this fuel is ignited by the ignition device I08. The position of the cone 48 is fixed by the position of the lever 48.

The turbine inlet temperature selector lever 88 is shown on the outside which corresponds to the lever 88 shown in Fig. 1.

Fig. 4 is similar .to Fig. 3 with the exception that the hydraulic mechanism for controlling the pitch of the propeller is manually controlled by the lever I90, the mechanism beingcontained inside the box I92. The shaft I88 is driven by the gears I84 which drive the governor inside the casing I92 and this governor controls the pitch of the propeller in a well known manner. The speed at which the governor controls the pitch is determined by the position of the manually controlled lever I90. In this-casethe control ofthe fuel from the pump I44 is controlled by means of the movable element 44 and the electrical conductors I18---I18' which alternately cause the small motors I98I98 to rotate the cam 200 clockwise and anti-clockwise and thus causes the valve 202 to open and close. The mechanism is contained in the casing 18. As before a storage'batte'ry I12 and a conductor I14 provides the motive power for the small electric motors I98I98. The valve 202 delivers the excess fuel-to the outlet passage I52. The main body of fuel is delivered through the passage 88 through the control device and then to the outlet I00 to the burners II4I I0 to the gas turbine I11. The turbine inlet temperature selector lever'88 is shown on the outside which corresponds to the lever 38 in Fig. 1. The position of the cone 48 is fixed by the lever 48. The governor is driven by bevel gears I84.

Fig. 5 is similar to Fig. 2 with the exception that the cone 48,. which was adjusted by the temperature control means in Fig. 2 is adjusted by the centrifugal means in Fig. 5. This time it is adjusted by a centrifugal governor 204 which is driven by theshaft I42 which shaft in its turn is driven by the shaft I88 which is driven by the gears I84 mounted on the compressor 88. control of the fuel is similar to that shown and described in Fig. 4. In this case there is no propeller. The turbine inlet temperature selector lever 38 is shown on the outside which corresponds to the lever 38 in Fig. 1.

Fig. 6 is a diagrammatic representation of the fuel/air ratio indicating mechanism corresponding to the right hand side of Fig. 1; In this Fig. '6 the fuel diaphragm 90 is shown in a vertical position connected to a link 208 which carries a pointer 208 which moves over a scale 2I0 to indicate fuel/air ratio. The left hand side of the fuel diaphragm 90 is subjected to the pressure in the fuel entrance 88. The right hand side of the diaphragm is subjected to the pressure in the outlet I00 downstream from the main fuel restriction 88, as modified by the restriction 92 and the valve 98.

The valve 98 is also connected to the air diaphragm which is responsive through the pipe 88 to the impact side of the Pitot tube. The suction side is connected through the pipe 18. As the fuel/air ratio falls the valve 98 moves to establish equilibrium between the diaphragms 80 and 90.

Fig. '7 shows diagrammatically the means for indicating turbine inlet temperature correspond- The ' .valve 82 to rise.

ing to the left hand side of Fig. 1. Valve 2I2 cor-- responds to the variable port 80 and imposes a .variable pressure in the chamber 84 to the left of the diaphragm 88. The pressure to the right of the diaphragm88 and to the right of the diaphragm I8 is that of the 20 pounds per square ratio and compression outlet temperature. Now

28; to the left of the diaphragm I8, is controlled by the valve 2 I 4 which corresponds to the variable port I8. The/temperature responsive element 2I8 correspondsto the temperature responsive ele ment I4 inFig. 1. The regulation of this pressure is by reason of the restriction 24. V The restrictions H8 and 24 are connected through a pipe 80 with the low pressure side of the oil pump not shown. The pressure on the diaphragms 88 and I8 is resistedby a spring 220 by means of the rod 2I8. The scale 222 indicates the'turbine inlet temperature by adding together the effect of variations in the temperature of the air entering the comibustion chamber and the rise in the combustion U chamber temperature due to the fuel/air ratio which determines the position of the valve 2 I2.

' Operation Assuming that the gas turbine has just been started then the compressor raises the temperature in the bulb I2 and the fuel/air ratio is decreased automatically as follows: The element I8 responds to the expansion of the element I4, and the port I8 is moved tothe right so that the area of the port I6 is decreased. The pressure in the chamber 26 is thus decreased and the diaphragm I8 is thus moved to .the right.

the influence of the spring 4|. 1 square inch pressure is thus applied to the right hand side of the element 44 which grounds the 1 electrical conductor to the left which is conductor I18 of Figs. 1, 2, 3, 4, and 5. This reduces the temperature by reducing the fuel flow. as described hereafter, relative to the air flow. This The; servomotor valve 42 is moved to the right against A 20 pound per turbine inlet temperature is equal to the compressor air temperature plus the rise in tempera-- ture in the combustion chamber. This; rise in temperature is a simple function of the fuel/air ratio. All attempts to re y on thermocouples and thermostats at the temreratures .of 1200, .1400", 1600 and 1800 F. have been generally unsatisfactoryw As the altitude varies the barometric element I02 expands and the port Ills-shifted to the left at high altitudes thus being reduced in area so that .a given flow of fuel at altitude producesa greater drop in-pressure and therefore calls for a greater drop in pressure to act on the air diaphragm 80. This detail is necessary to maintain constant fuel/air ratio at altitude for a fixed position of cam and a -iixed temperature in the compressor outlet I0. 1

In Fig. '2 the temperature control is obtained from the two electrical conductors I'I8-I'I8. As

.the element 44,'moves to the right and'left, as

thusdescribed, it causes the electric motors i88I|0 to rotate. The worm I82 is thus turned in opposite directions. The cone 48 is thus moved in and out of the outlet from the gas turbine.

When it moves to the right the temperature risesand when it'moves to the left the temperature falls. Meanwhile it is necessary to limit the top speed of the compressor turbine unit. 88--I| I.

This is accomplished by the gear wheels I84 which rotate at a speed proportional to the speed of the change in fuel/air ratio causes the servomotor creases the flow at the bypass 84 which increases the pressure drop at the fuel restriction 82. .This restores equilibrium and moves the servomotor valve 82 back into the neutral position in which it is shown. Meanwhile the port 80 has moved to the right increasing the area of the port 80 which raises the pressure in the chamber 84 which restores the servomotor valve 42 to the neutral position in which it is shown.

If the lever 88 is moved clockwise the servomotor valve 42 is moved to the left, the element 44 is moved to the right, the electrical conductor I18 is grounded and the controls are moved so as to increase the fuel flow relative to the air flow. This causes the servomotor valve 82 to descend which causes the piston 84' to move to the left and the valve 88 to move towards the closed position and this causes the port 80 to move towards the closed position also. I

The pressure in chamber 84 falls so that the servomotor valve 42 moves to the right and restores the servomotor valve 42 to the neutral position in which it is shown. The compression of the spring 4| varies with every position of the cam 40. Hence, with every position of the cam turbine. A centrifugal governor contained in the casing I48 rotates and allows fuel to escape from the governor casing. I48 to the fuel return outlet I82 past the return valve 282. v

tank I.I8, past the Fuel is supplied from the screen I88, through the passage I88 to the boost pump I40 tothe high pressure pump I44, which delivers'fuel through the passage I48, to the governor casing I48. The speed at which the gov-' ernor is effective is determined by the regulator leverI80, which. in this case is manually controlled. Themanual control lever 88 and the manual control lever I88 are thus available for selecting the safe maximum" temperature and the safe maximum speed.

In Fig. 3 the gas turbineis arranged todrive a variable pitch propeller through a pair of spur gears I82I84. In this case the pitch control device is contained in the housing I" which contains two small electric motors I88-I88. I88 is connected to the conductor I18 which is grounded when the element 44 moves to the left. When the element moves to the right the conductor I18 is grounded and the small. motor I88 is thus operated. The variations in the'pitch of the propeller I80 thus controls the temperature as se-.

. lected by the position of the lever 88. As before the centrifugal governor, contained in the casing I48, and driven by the spur gears I84. controls the escape of the fuel through the return passage I82 past the return valve 202,. The speed and load of the propeller driven gas turbine is thus con- 7 trolled, at the temperature selected by the position of the lever 88. The speed at the position of 88 is determined by the position of the lever I80. The cone is adjusted manually and is held in a fixed position by thelever 48.

In Fig. 4 which is similar to F18- 3 the variable pitch propeller I88 is controlled by a centrifugal governor contained in the casing I82. This centrifugal governor is driven by means of the bevel gears 88, which are driven from the turbine by the 40 ther is a d ni Value to the Bum fuel/811' :5 gears I84. The manually controlled lever I88 de- 9 termines the speed directly and indirectly and it determines the pitch of the propeller in a well known manner. The temperature of the combustion chamber is then controlled by the fuel flow. Tin: casing 18 contains the two small electric motors l96-l98 which are alternately energized whenever the element 44 moves to the right or left to ground one of the conductors I'I6-I'|8. The cam 200 is thus rotated clockwise and anticlockwise to raise and lower the valve 202 and to vary the return of the fuel from the casing 18 through the. pipe I52 to the high-pressure fuel pump I. As in Fig. 3 cone element ll is held in a fixed position by the lever 45.

- Fig. 5 like Fig. 2 has no propeller as it depends purely on jet propulsion. In this case the position of the cone 4 8 is determined by a centrifugal governor 2M driven by the shaft 2, which shaft is driven by the shaft I58, which shaft is driven by the shaft I 66, which shaft is driven by the gas turbine 68 through the bevel gears I54. Actually the servomotor would be used for the control of the cone ll but this servomotor has been omitted for the sake of simplicity. In this case, as in Fig. 4, the valve 202 is controlled by the cam 20!! which determines the return flow through the pipe I 52 and the position of the valve 200 is determined by the element 44 as described above. As before the lever 38 thus determines the temperature through the gas turbine I16, the speed being determined by the position of the cone 8 which is controlled by the governor 204.

What I claim is:

1. A temperature control device for an air compressor connected to a gas turbine having a combustion chamber between the compressor and the turbine, comprising a fuel entrance to said control device, a fuel exit, a fuel restriction therebetween, a bypass around said fuel restriction, a second fuel restriction located in said bypass, a fuel diaphragm responsive to the drop in pressure at said second restriction, an air entrance to said air compressor, differential pressure means in said air entrance responsive to the air flow, an air diaphragm responsive to said air differential pressure, a third fuel restriction in series with said second fuel restriction, a valve in said third fuel restriction, means connecting said valve to both of said diaphragms so that an increase in air flow tends to open said valve and an increase in fuel flow tends to close said valve, means responsive to the temperature of the compressed air entering said combustion chamber to vary the in et temperature of said gas turbine, additional means responsive to the position of said valve to Jointly control with the first mentioned means the inlet temperature of said gas turbine.

2. A device as set forth in claim 1 in which there is a conical outlet jet leading from the gas turbine, a cone therein, means for moving said cone to vary the load on said gas turbine and the load and speed of said gas turbine, gas turbine speed responsive means adapted to control the position of said cone so as to regulate the speed of the turbine, means whereby said temperature control means are adapted to control the quantity of fuel supplied to the gas turbine to limit the temperature of the gas striking the turbine blades.

3. A device as set forth in claim 1 in which the gas turbine drives a variable pitch propeller and in which the temperature control means controls the gas turbine temperature by varying the pitch of said propeller, gas turbine speed responsive means which are adapted to control the fuel supply. 4

4. A device as set forth in claim 1 in which the gas turbine drives a variable pitch propeller, a

speed responsive governor for said variable pitch propeller to regulate the turbine speed and in which there are means for controlling the supply of' fuel connected to said temperature control means.

5. A temperature control device for an air compressor connected to a gas turbine having a, combustion chamber between the compressor and the turbine comprising a fuel entrance to said control device, a fuel exit, a fuel restriction therebetween, abypass around said fuel restriction, a second fuel restriction located in said bypass, a fuel diaphragm responsive to the drop in pressure at said second restriction, an air entrance to said air compressor, differential pressure means in said air entrance responsive to the air flow, an air diaphragm responsive to said air differential pressure, a third fuel restriction in series with said second fuel restriction, a valve in said third fuel restriction, means connecting said valve to both of said diaphragms so that an increase in air flow tends to open said valve and an increase in fuel flow tends to close said valve, means responsive to the position of said valve to control the inlet temperature of said gas turbine.

6. A device as set forth in claim 5 in which there is a conical outlet jet leading from-the gas turbine, a cone therein, means for moving said cone to vary the load on said gas turbine and the load and speed of said gas turbine, gas turbine speed responsive means adapted to control the position of said cone so as to regulate "the speed of the turbine, means whereby said temperature control means are adapted to control the quantity of fuel supplied to the gas turbine to limit the temperature of the gas striking the turbine blades,

7. A device as set forth in claim 5 in which the gas turbine drives a variable pitch propeller and in which the temperature control means controls the gas turbine temperature by varying the pitch of said propeller, gas turbine speed responsive means which are adapted to control the fuel supply.

8. A device as set forth in claim 5 in which the gas turbine drives a variable pitch propeller, a speed responsive governor for said variable pitch propeller to regulate the turbine speed and in which there are means for controlling the supply of fuel connected to said temperature control means.

9. A temperature control device for an air compressor connected to a gas turbine having a combustion chamber between the compressor and the turbine comprising a fuel entrance to said control device, a fuel exit, a fuel restriction therebetween, a bypass around said fuel restriction, a second rerestriction in said bypass, a fuel diaphragm responsive to the drop in pressure at said second restriction, an air diaphragm responsive to the air fiow through said gas turbine, a third restriction in series with said second restriction, a valve in said restriction, means connecting said valve to both diaphragms so that an increase in air flow tends to open said valve and an increase in fuel flow -tends to close said valve, barometric means tending to close said first mentioned restriction at altitude, means responsive to the temperature of the air entering the combustion chamber of said gas turbine and to the position of said valve for jointly controlling the temperature 11 from the combustion chamber of the gases issuing they strike the of said gas turbine just before blades of the gas turbine. v 7

10. A device as set forth in claim 9 in which there is a conical outlet jet leading from the gas turbine, a cone therein, means for moving said cone to vary the load on said gas turbine and the load and speed of said gas t rbine, gas turbine speed responsive means adap ed to control the position of said cone so as of the turbine, means whereby said temperature control means are adapted to control the quantity of fuel supplied to the gasturbineto limit the temperature of the gas striking the turbine blades.

11. A device as set forth in claim 9 in which to regulate the speed the gas turbine drives a variable pitch propeller and in which the temperature control means controls the gas turbine temperature by varying the means.

13. A temperature-control device for an air compressor connected. to a gas turbine having a combustion chamber between the compressor and the turbine comprising a fuel entrance to said control device, a fuel exit, a fuel restriction therebetween, a bypass around said fuel restriction, a second restriction in said bypass, a. fuel dia; phragm responsive to the drop in pressure at said second restriction, an air diaphragm responsive to the air flow through said gas turbine, a third restriction in series with said secondrestriction, a valve in said restriction, rneans connecting said valve to both diaphragms so that an increase in air flow tends to open said valve and an increase in fuel flow tends to close said valve, barometric means tending to close said first mentioned'restriction at altitude, means responsive to the position of said valve to control the inlet temperature of said gas turbine.

14. A device as set forth in claim 13 in which there is a conical outlet jet leading fromthe gas turbine, a cone therein, means for moving said cone to vary the load on said gas turbine and the load and speed of said gas turbine, gas turbine speed responsive means adapted to control the position of, said cone so as to regulate the speed of the turbine, means whereby said temperature control means are adapted to control the quantity of fuel supplied to the gas turbine to limit the temperature of the gas striking the turbine blades.

15'. A'device as set forth in claim 13 in which the gas turbine drivesa variable pitch propeller .and'in which the temperature control means controls the gas turbine temperature by varying the pitch of said propeller, gas turbine speed re- .sponsive means which are adapted to control the fuel supply. 7 I

16.. A device asset forth in claim 13 in which the gas turbine drives a variable pitch propeller, .a speed responsive governor for said variable pitch propeller to regulate the turbine speed and in which there are means for controlling the supply of .fuel connected to, said temperature control means.

.17. In a gas turbine having a combustion charriber, fuel and air supply conduits, air flow responsive means located'in said air conduit, a restriction in said fuel conduits, two diaphragms responsive oneto theair flow and one to the fuel flow arranged so as to oppose each other, auto matic balancing means therefor connected to both of the two dlaphragms and consisting of a valve which reduces the effect of the fuel pressure drop at said restriction, the position of said valve thus reflecting the fuel/air ratio, means responsive to the temperature ofthe air entering the combustion chamber, said means being coupled to the balancing means so that some function of fuel to air ratio is 'added to said means responsive to the temperature of the air entering the combustion chamber, manual means for selecting the value of thissum, automatic means responsive to said selected sum for varyingthe air flow rel- Y ative to the fuel flow so as to give the said sum the value'selected. 18. In a gas turbine having ,a combustion chamber, fuel and air supplies therefor together with opposing air and fuel flow responsive means,

means responsive to the unbalance between the opposing fuel and air responsive means adapted to vary the eflect of the fuel flow so that the 'fuel and air flow responsive means may balance each other. automatic means responsive to the position of said balancing means for'varying the air flow, yielding means opposing the said automatic means, a manually operated cam acting on said yielding means so as to select the desired fuel/air. I ratio in said combustion chamber.

ANDREW WILLIAM can, in.

REFERENCES orrsn "lhe following references are of record in the die of this patent: 

